Optical device for compensating the movement of the film in cinematograph apparatus



May 26, 1925. 1,539,579

S. K HAFZSKI OPTICAL DEVICE FOR COM SATING THE MOVEMENT OF THE FILM IN CINEMATO PH APPARATUS Filed Aug. 1921 2 Sheets-Sheet 1 "magma;

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May 26, 1925. 1,539,579

S. KUCHARSKI OPTICAL DEVICE FOR COMPENSATING THE MOVEMENT OF THE FILM IN CINEMATOGRAPH APPARATUS Filed Aug. 51, 1921 2 Sheets-Sheet 2 IrJvErJI-U a ,m-uFuJEYs Patented May 26, 1925.

i v 1,539,579 UNITED STATES PATENT OFFICEQ' STANIBLAUS KUOHAIRSKI, OF CHARLOTTENBURG, NEAR BERLIN, GERMANY, LS-

SIGNOR TO AUTOSCOPE LTD., OF LONDON E. C. 2, A BRITISH COMPANY.

OPTICAL DEVICE FOR COMPENSATING THE MOITEMENT OF THE FILL! IN CINEIA'I'O- GRAPH APPARATUS.

Application filed August 31, 1921. Serial No. 497,305.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF KARCE 3, 1921, 41 STAT. In, 1818.)

To all whom it may concern:

Be it known that I, STANISLAUS KUCHAR- sKr, engineer, a citizen of Germany, residing at Charlottenburg, near Berlin, Dernburgstrasse 45, Germany, have invented certain new and useful Improvements in Optical Devices for Compensating the Movement of the Film in Cinematograph Apparatus (for which I have filed applications in Germany, filed May 15', 1920; Great Britain, filed September 30. 1920; and Germany, filed May 15, 1920), of which the following is a specification.

The invention relates to devices for compensating the movement of the film in cinematograph apparatus by means of a mirror. The known arrangements require a consider able space because the mirror must be in serted in the path of the rays of light and the objective if it is arranged between the film and mirror must embrace a field of view of the image corresponding to two separate images, which requires a long focal distance.

According to the invention, the space required is lessened by combining together the mirror and the objective into a single member. The mirror and the objective are either combined into a movable prism in which one surface forms the. mirror and one or more of the remaining surfaces the lenses part objective are united together to form a prismatic objective, but are relatively movable in a predetermined manner.

An example of a construction according to the invention is shown diagrammatically V in Fig. 1 of the accompanying drawing.

plciyed.

n Fig. 1, L is the source of ii ht in front of which is the condenser K. e film is moved continuously in front of the condenser throu h the window F which in this case is curve Opposite to the windows is the prismatic mirror which comprises the mirror S and the two lenses 0 and O which together form the objective. The mirror and the lenses are combined in a casing which can be rotated about an axis and is thence reflected laterally through the.

lens 0 to the screen. In the same way the other points of the image are thrown on the screen.

In order to compensate optically for the movement of the film the prismatic mirrorv is oscillated in known manner for thispurvpose about the axis D. In Fig. 2 it is assumed that the film has been moved on so that the point I) is in the optical axis of the apparatus. At this moment by means of an eccentric or other device. the prismatic mir:

roris rotated so that it is not the image of the point 7; which is projected by the mirror S and the lenses on to the centre of the screen. but the middle point 11: of the image -7). I

The prismatic mirror may, as shown in Fig. 3. be formed in a single piece. of which the plane surface S forms the mirror and the curved surfaces 0. o" the objective.

In Fig. 4 the prism has three plane surfaces. The perpendicular surfaces are, however. converted into an objective by cementing to them one or more lenses 0. 0'. A11 achromatic combination is shown in Fig. 4 of an objective consisting of a pairof planoconvex and concavo-convex lenses 0", O". The prism may be of the same glass as the plano-convex lenses, which can be made of one piece with the prism. so that only the concavo-convex lenses need be cemented. By the construction of the lenses 0", 0 according to Fig. 6 a double anastigmatic lens is obtained.

Fig. 7 is similar to Fig. 1, but the mirror S is not lane but curved It may in this case be ei er a concave mirror or a convex mirror according to whether the construction of the lenses of the objective, which naturally also are made achromatic .or anastigmatic, require a converging or a divergi lens between them.

n the inclined sition of the mirror (Fig. 2) when the de 'iation is greatest, the optic axis of then lens 0 falls on a point .r' midway between 6' and b. At this moment, however, the whole image b, I) should be embraced so that it is obvious that the field of view of the objective must be raised by half. If the three parts, the mirror and the two parts of the ob ective, were independent of one another, as shown in Figs. 8 and 9, the part O might be moved through an angle corresponding to the image the mirror through half this angle. the part 0'' remaining stationary. In this device the rays of light, which cone from the middle point of the image which at that time is to be ro- 'ected, coincide with the optic axes of th elves of the objective and no raising of the field of view occurs. The rotation of one half of the objective through the whole a le cornding to the movement of the m and that of the mirror-through half this angle ofier no diflic'ulty and can be attained in difierent ways; for example, obviously, by two eccentrics. The full movement of the objective'O may be effected by means of an eccentric and the half movement of the mirror by means of a system of parallel levers in connection with this part.

Figs 10 and 11 represent the same method carried out with a prism. In these figures both surfaces of the prism are curved so that the middle points of the curves coincide with the rotary axis of the prism. Close to the curved surfaces of the prism but not cemented to them are the two diverging lenses O. and 0" so arranged that as described in connection with Figs. 8 and 9 one of these (0) makes the full movement of the film and the other (0") is stationary. Since all points of the curved surfaces of the prism are at the same distance from the centre D, the movement of the rism relatively to the 'lenses 0" and O has no efiect on the optical working of the device.

Figs. 12 and 13 represent the same method with the employment'of the mirror and a single objective. In this case the objective is moved through the whole angle corresponding to the change of the film, the mirror through half the angle. If the objective is placed where the part O is shown in Fi -8-9, the objective remains stationary an only the mirror is moved.

I claim:

1. In a device of the ,type described,

means for compensating the movement of the film, comprising a mirror for reflecting the li ht from the film, associated with an objective forming with said mirror a movable prism means for oscillatin the prism in synchronism with the film-fe ing means.

2. In a device of the type described,

'means for compensating the movement of the firm, comprisin a mirror for reflecting the light from the fifim, and an objective disposed at an angle to said mirror, said means comprising a movably mounted unit means for oscillating the unit in synchronism with the film-feeding means,

3. In a device of the type described, means for compensating the movement of the film, comprising a mirror for reflecting the li ht from the film, in combination with an o jective disposed to form with said mirror a movable prism, the lenses of said objective forming two sides of the prism and the mirror forming the remaining .side means for oscillating the prism in synchronism with the film-feeding means.

4. 'In a device of the type described, the combination of a film guide with a movable prism for compensating the movement ofthe film, said prism comprising a lens disposed on one side thereof and forming the objective, and a mirror disposed on the other side thereof and means for oscillating the prism in synchronism with the filmfeeding means.

5. In a device of the type described, the combination with a film guide, of means for compensating the movement of the film, said means comprising a mirror having a curved surface, combined with an objective to form a movableprism, said mirror forming one side thereof and the lenses of said objective forming the other side thereof.

6. In a deviceof the ty described, the combination of a film gui e with a means for compensating the movement of the film, said means comprising a mirror and an objective arran d in generally triangular form, said mirror and a part of said objective being movable and means for oscillating the mirror and objective in synchronism with the filmfeeding means.

7. In a device of the class described, the combination of a film-guide with a device for compensating the movement of the film, said device comprisin an integral 'prism havin a reflecting sur es andtwo surfaces curve so as to form a double objective-and means for oscillaltin the prism in synchronism' with the -feedmg means.

In testimony whereof I have afixed my signature in presence of two witnesses.

STANISLAUS KUCHARSIH.

Witnesses:

ALVIN Haxsomm, Gnsrav Pm'sox. 

